Climate change is causing UK plants to flower almost a month earlier on average, according to a study.
Just as autumn leaf fall is being delayed by warmer weather, flowers are appearing earlier on trees and shrubs.
But while some might welcome these untimely blooms, scientists are warning of the risks.
They say if the trend continues, there are knock-on effects for birds, insects and whole ecosystems.
Ecological mismatch may kick in, which would have a dramatic effect “on the functioning and productivity” of nature and farming, said lead researcher, Prof Ulf Buntgen of the University of Cambridge.
Global warming is causing spring to arrive early and autumn to come late in many places, and not all plants and animals are adapting at the same rate.
Scientists warn that if species get out of sync with each other, this could have disastrous consequences – a concept known as ecological mismatch.
Pollen, nectar, seeds and fruits of plants are important food resources for insects, birds and other wildlife. And if flowers appear too early they can be hit by frost, damaging the harvest of fruit trees.